U.S. Pat. No. 2,974,412 A discloses an attachment comb unit for an electric hair clipper, the comb unit comprising a plastic comb forming comb teeth, and a sheet metal back portion that is resiliently clamped against a channel-shaped sheet metal support element that is fixedly attached to a stationary blade of the hair clipper. The plastic comb and the sheet metal back portion are slidably mounted to the sheet metal support element by means of a clamping screw that engages a slot at the sheet metal back portion.
DE 446 264 C discloses a hair clipper having a blade set and an adjustable comb for changing the cutting height during cutting, wherein the comb is movable with respect to the blade set, wherein the comb is pivotably attached to a push piece, and wherein a leaf spring is provided between the push piece and the comb that urges the comb against the blade set.
EP 2 105 267 A1 discloses a hair clipper comprising a main body portion, a comb-shaped blade unit having a pair of blades comprising a movable blade and a stationary blade, and a spacing comb having a comb portion associated with the stationary blade, wherein the comb portion is pivotable between an engagement state and an out-of-engagement state.
Hair cutting appliances, particularly electric hair cutting appliances, are generally known and may include trimmers, clippers and shavers. Electric hair cutting appliances may also be referred to as electrically powered hair cutting appliances. Electric hair cutting appliances may be powered by electric supply mains and/or by energy storages, such as batteries, for instance. Electric hair cutting appliances are generally used to trim or remove (human) body hair, in particular facial hair and head hair to allow a person to have a well-groomed appearance. Frequently, electric hair cutting appliances are used for cutting animal hair.
U.S. Pat. No. 6,968,623 B2 discloses a hair trimmer comprising a body, a cutting head including a blade set, an adjustable comb, wherein the comb is movable with respect to the blade set, an electric motor for driving the blade set to effect a cutting action, and an actuator assembly that is capable of moving the comb with respect to the blade set between a fully retracted position and a fully extended position, the actuator assembly comprising a comb carriage, a comb button connected to the comb carriage, wherein the comb button is actuatable to adjust the position of the comb relative to the blade set, and a lock button movable with respect to the comb button, wherein the lock button selectively prevents and permits movement of the comb button relative to the body. Consequently, manual adjustment of the length of the comb is enabled.
A comb for a hair cutting appliance, particularly a spacing comb, generally may be arranged as an attachable comb or an integrally formed comb. A spacing comb generally spaces a blade set of the hair cutting appliance away from the skin when the appliance is moved in a moving direction with respect to the skin during operation. Consequently, the spacing comb may enable to process/cut hair to a desired length, i.e. to a desired length of remaining hair at the skin.
Conventional hair cutting appliances may be fitted with a set of attachment combs, each of which associated with a distinct hair length. Consequently, a user of the appliance basically needs to replace an attachment comb by another one to change the hair cutting length. Furthermore, manually adjustable comb attachments are known, as disclosed in U.S. Pat. No. 6,968,623 B2. Furthermore, also powered adjustment combs have been presented in recent years, as for instance disclosed in EP 2 500 153 A2. Typically, powered adjustment combs comprise a movable comb portion that is movable with respect to a blade set of the hair cutting appliance, wherein the movable comb portion is coupled to an actuator, particularly to an electromotor and/or an electric powertrain.
Using spacing combs has the benefit that an even hair length may be achieved, for instance a length of 3.0 mm, 6.0 mm, 9.0 mm, etc. Hence, particular short haircuts, three-day beards and similar procedures may be simplified.
Generally, as shown in U.S. Pat. No. 6,968,623 B2 and in EP 2 500 153 A2, a spacing comb, particularly an adjustable spacing comb, is attached to a cutting head of a hair cutting appliance in such a way that a frontal portion of the teeth of the comb extends beyond, or even covers, the tips of the blade set of the hair cutting appliance, as seen in a frontal direction that is basically aligned with a movement direction of the appliance along the skin. In this way, on the one hand, a considerable hair catching capacity of the combined blade set with the attachment comb is ensured. This involves that the comb teeth are arranged to lift the hair when the appliance to which the comb is attached is moved through the haired portion. However, on the other hand, this involves that even in a retracted state of the adjustment comb, the tips of the teeth thereof protrude beyond the tips of the stationary blade. Further, in some embodiments, the teeth of the comb are provided with a locking recess which may be engaged by the teeth of the stationary blade of the blade set. Hence, the attachment comb is also properly fixed to the toothed portion of the blade set in a positive fit fashion.
A further goal of the embracing design of the teeth of the attachment comb is to prevent hairs from entering a gap between the teeth of the stationary blade and the teeth of the attachment comb, and being trapped or being jammed in the gap. This would actually result in hairs becoming ripped out.
However, the above arrangement has some drawbacks. First, even in a fully retracted state, at least the tips of the teeth of the attachment comb protrude beyond the teeth of the blade set. This somewhat obstructs the cutting zone. Hence, trimming and styling operations are somewhat complicated due to impaired visibility conditions. Further, as the attachment comb somewhat blocks and covers the frontal end of the blade set, the reachability of the appliance is deteriorated. This appears, for instance, when a mustache on the upper lip is trimmed and styled. It is then often difficult, if not impossible, to reach the transitional edge between the upper lip and the nose with the teeth of the blade set. In practice, this often involves that the uppermost hairs that are very close to the nose cannot be adequately trimmed to the desired length. Similar problems may occur when sideburns are processed, when head hair in the vicinity of the ears is processed, and/or when sharp edges between shaved and non-shaved portions are processed and groomed.
There is thus still room for improvement in spacing comb arrangements and, more generally, length adjustment mechanism for hair cutting appliances.